A fluid dynamic bearing device is a bearing device in which pressure is generated by a dynamic pressure action of a fluid generated in a bearing gap through relative rotation of a bearing member and a shaft member inserted into the inner periphery of the bearing member and which supports the shaft member in a non-contact fashion with this pressure. The fluid dynamic bearing device is endowed with various features such as high speed rotation, high rotational accuracy, and low noise, and is suitable as a bearing device for use in a spindle motor for a disk drive in an information apparatus, for example, a magnetic disk device such as an HDD, an optical disk device such as a CD-ROM, a CD-R/RW, or a DVD-ROM/RAM, or a magneto-optical disk device such as an MD or MO, a polygon scanner motor for a laser beam printer (LBP), a projector color wheel motor, or a small motor for an axial fan or the like.
For example, as shown in FIG. 19, in a fluid dynamic bearing device to be incorporated into the spindle motor of a disk drive apparatus such as an HDD, there are provided a radial bearing portion R supporting a shaft member 20 radially in a non-contact fashion and a thrust bearing portion T supporting the shaft member in a thrust direction in a non-contact fashion. As a bearing for the radial bearing portion R, there is a publicly known fluid dynamic bearing provided with grooves (i.e., dynamic pressure grooves) for dynamic pressure generation provided in an inner peripheral surface of a bearing sleeve 80 which is formed in cylindrical shape. As the thrust bearing portion T, there is a publicly known fluid dynamic bearing provided with dynamic pressure grooves in, for example, both end surfaces of a flange portion 20b of the shaft member 20 or in surfaces opposed thereto (e.g., an end surface 81 of the bearing sleeve 80 and an end surface 61a of a roof member 61 fixed to a lower portion of the housing 70) (see, for example, Patent Documents 1 and 2).
In many cases, in a fluid dynamic bearing device of this type, the bearing sleeve 80 is usually fixed to a predetermined position of the inner periphery of the housing 70, and there is provided a seal member 90 at the opening of the housing 70 in order to prevent lubricant supplied into the inner space of the housing 70 from leaking to the exterior.
[Patent Document 1] JP 2003-65324 A
[Patent Document 2] JP 2003-336636 A